1. Field of the Invention
The present invention relates to a camera-shake preventing device for preventing an image deflection due to a camera-shake by driving a part of an optical system on detecting the camera-shake.
2. Related Background Art
A known device has hitherto prevented a camera-shake by the following steps. The camera-shake caused by a hand movement is detected by use of a camera-shake detecting unit such as an angular velocity sensor and an acceleration sensor consisting of a piezoelectric element, etc.. A proper camera-shake compensation quantity is computed from this detected camera-shake. An optical path is compensated by moving a compensating lens up and down or right and left on the basis of this compensation quantity.
In the conventional camera-shake preventing device, the detection and compensation of the camera-shake start from a half-depressed state of a release button. For this reason, if the release button remains half-depressed for a long time, the camera-shake preventing device has to be operated long. A large amount of electric power is consumed by the sensors and a motor that constitute the device. This leads to a consumption of the battery. Consequently, there arise inconveniences, wherein the device does not normally operate during photographing, or the camera body also does not normally operate when the power is supplied from the battery of the camera body.
Contrastingly, for detecting and compensating the camera-shake after the release button has been full-depressed, the battery consumption may be small. There is, however, such an inconvenience that an effect of compensating the camera-shake can not be confirmed beforehand by an observation of the photographer through a viewfinder.